This invention relates generally to aircraft ventilation systems and, more specifically, to control of aircraft crew rest area ventilation air systems.
Commercial aircraft around the world often undertake flights in excess of eight hours in length. Because of a need for adequate rest facilities for the flight crew and cabin crew members, rest areas are provided within the aircraft for use by the crew members while the aircraft is in flight or on the ground. Typically, the rest areas are relatively small, such as, single person units remotely located in the vicinity of the aircraft""s cockpit.
Ventilation systems in the rest areas are typically tied directly into the aircraft""s main ventilation system. Obtaining and maintaining a habitable environment within the rest areas and complying with safety regulations has been a problem due to a number of factors. These factors include a relatively large size of the main ventilation system of the aircraft, wide ranging atmospheric environmental conditions, a relatively small size of the rest areas, and locations of the rest areas in remote parts within the aircraft.
Cool air pulled from the aircraft""s main air conditioning pack is often excessively cold for relatively small rest areas. If the aircraft""s main ventilation system is continually running, the rest area is too cold to occupy until the rest area can be adequately heated. Conversely, if the ventilation system is shut down for any appreciable length of time, especially in warmer climates, the rest areas can become too hot to occupy. In either case, the rest areas and the items within the rest area represent a thermal mass which, inherently, increases the time required to heat or cool the space to a habitable level. This additional length of uninhabitable time reduces the amount of time a crew member can rest when the crew member has the time available for resting. This can lead to some crew members not receiving enough rest.
Another problem with pulling air directly from the main air conditioning pack is the adverse effect on ventilation system components. More specifically, under certain atmospheric conditions, such as those encountered on the ground or in flight less than 25,000 feet, icing can occur in the ventilation system. Icing can detrimentally affect operation of shut-off valves and other components downstream from the air conditioning packs, thus creating an undesirable or uncertifiable ventilation condition.
Therefore, there is an unmet need in the art for a system for maintaining habitable conditions in aircraft crew rest areas.
The invention provides a reliable system for controlling crew rest air ventilation temperature such that the crew rest area climate is continually maintained in a habitable condition throughout ground and all flight operations.
The present invention provides a temperature control system for an aircraft ventilation system that couples with existing aircraft upstream ventilation system architecture and downstream ventilation system architecture. The temperature control system includes an air duct arranged to receive a volume of ventilation air from the upstream ventilation system architecture and transfer the volume of air to the downstream ventilation system architecture. At least one heater is interposed within the duct and is arranged to heat the ventilation air. Additionally, at least one temperature sensor that is in thermodynamic communication with the volume of air within the duct is located downstream from the at least one heater and is arranged to determine an actual temperature of the ventilation air. A controller is in electrical communication with the at least one heater and the at least one temperature sensor. The controller is programmed with a predetermined range of temperatures above the freezing point of water. The controller is arranged to control the heater responsive to a comparison of the actual temperature of the ventilation air to the predetermined range of temperatures. The controller maintains the actual ventilation air temperature within the predetermined range of temperatures such that formation of ice is minimized in the aircraft ventilation system.
In accordance with further aspects of the invention, the present invention provides a method of preventing icing conditions in an aircraft ventilation system. The method includes receiving ventilation air from an upstream ventilation system architecture of an aircraft ventilation system, passing the ventilation air through a heater at a first location and sensing an actual ventilation air temperature at a second location downstream from the first location. A controller compares the actual ventilation air temperature with a predetermined range of temperatures above the freezing point of water, and subsequently controls the heater responsive to the comparison of the actual air temperature with the predetermined range of temperatures to maintain the actual air temperature within the predetermined range of temperatures. The continual sensing, comparing and controlling of the air ventilation temperature minimizes the formation of ice in the aircraft ventilation system.